Help w/ speaker for 16F690 and SOUND command

[bhiggenson]

I removed the sound command from my main program just so I could focus on that. The only line of code I have now is:

sound portc.0, [100,100]

the LED tied to portc.0 lights up, but all I get is an initial click from the speaker. I've tried 6-10 different capacitors and that doesn't help either.

Anyone have any other thoughts? I've tried changing the tone from 1 to 127 and no change. When I use one of the "white noise" tones, say 157, then I do see the LED flicker and the speaker crackles with the LED flicker.

I wish I had a scope, but I don't.

Any other thoughts?

[Byte_Butcher]

PORTC.0 is also an analog port with comparator and ADC. Is the port configured correctly to be a digital output?
I know the sound command *says* it automatically makes it an output, but....?

Have you tried the speaker on a different port? maybe yer PIC is busted.

Any chance you have the PIC's oscillator set to the wrong frequency and it's outputting your sound at some super high "only dogs can hear it" frequency?

Have you tried a really low note setting like 10 or 20?

That's all that comes to mind now.


steve

[Byte_Butcher]

Oh, and what's your power supply?

A speaker is a pretty low impedance load. Any chance that when the speaker turns on it drags your supply voltage down to unhappy levels?

[bhiggenson]

I downloaded an application that uses the sound card and provides AC osciliscope capabilities (no DC). With no speaker (load) attached I see a spike when the sound starts and a matching inverted spike when the sound stops and since I don't think it does DC I expect it's shifting to a TTL high during this period. There is no detectable waveform present. When I switched back to the note 157 (white noise) I DO see a square wave form that is random in nature. Still no clue here why it's not producing any noise for the 1-128 notes.

[Archangel]

From the Data sheet: ANSEL and ANSELH must be configured to use port C as I/O.

;@MyConfig =  
@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON  
@MyConfig = MyConfig & _MCLRE_ON & _BOR_OFF 
@ __config  MyConfig 

DEFINE OSC 4
PortA = 0
PortB = 0
PortC = 0
TRISA = 1
TRISB = 0
TRISC = 0
i var byte
ANSEL = 0
ANSELH = 0
CM1CON0 = 0
CM2CON0 = 0
main:

portc = 0
pause 500

for i = 1 to 15; step -1


portC = i
i=i  << 1 
pause 250
next i
sound portB.6, [120,2,124,2,123,2,121,2]
sound portC.6, [120,2,124,2,123,2,121,2]
goto main
end

Without them sound works on PortB but not PortC, the code snippet above is configured to use the MicroChip low parts count demo board.

[Byte_Butcher]

From the Data sheet: ANSEL and ANSELH must be configured to use port C as I/O.

Uh huh... that would've been my first guess.

[bhiggenson]

Thanks very much for the help. I didn't have ANSELH and that was the missing link. Very much appreciated!